EN 10025-6 S890Q High Strength Structural Steel Plate

1. What is S890Q High Strength Structural Steel Plate?

S890Q high-strength structural steel plate (Material No. 1.8940) is a quenched and tempered (QT) fine-grained, high-strength, low-alloy structural steel as specified in EN 10025-6, supplied in a quenched and tempered condition. Its minimum yield strength is 890 MPa, and its tensile strength ranges from 940 to 1100 MPa.

S890Q high-strength structural steel plate combines ultra-high strength with good weldability, formability, and fatigue resistance, enabling lightweight structural design for heavy-duty components. It is widely used in cranes and lifting equipment, mining and earthmoving machinery, offshore engineering, bridges and heavy structures, transportation, and specialty vehicles.

2. Grade Designation Meaning

S: Structural Steel

890: Minimum yield strength (ReH) 890 MPa (for thickness ≤50 mm)

Q: Quenched and tempered

1. The chemical composition achieves a balance of high strength and toughness through alloying elements (such as Cr, Mo, Ni) and microalloying elements (Nb, V, Ti), while controlling the content of harmful elements (P, S).

2. Cr and Mo enhance hardenability and strength; Ni improves low-temperature toughness; Nb, V, and Ti refine the grain structure, increasing strength and toughness; low P and S reduce inclusions and decrease brittleness.

Note: The values vary slightly with thickness, as the cooling rate during quenching differs, affecting the final microstructure.

1. Ultra-high strength, significantly enhancing load-bearing capacity

While meeting the same structural strength requirements, the use of S890Q allows for thinner steel plates, reduces the structure’s dead weight, increases the equipment’s load-bearing capacity, and minimizes steel consumption.

2. Excellent strength-to-weight ratio

It is particularly suitable for structures that require both lightweight construction and high load-bearing capacity, such as cranes and lifting equipment, mining machinery, construction machinery, heavy-duty transport equipment, high-load steel structures, bridges and large structural components, and offshore engineering equipment.

3. Good low-temperature impact toughness

S890Q possesses good impact toughness, with the following Charpy V-notch impact energy absorption requirements:

0°C: Longitudinal ≥ 40 J, Transverse ≥ 30 J

-20°C: Longitudinal ≥ 30 J, Transverse ≥ 27 J

Therefore, S890Q not only offers high strength but also meets structural safety requirements in certain low-temperature environments.

4. Quenched and Tempered Condition: Balance of Strength and Toughness

S890Q steel plates are supplied in a quenched and tempered (QT) condition. This heat treatment process achieves high strength while maintaining a certain level of ductility and toughness, serving as a crucial foundation for S890Q’s application in high-strength structural applications.

5. Good Suitability for Engineering Processing

S890Q can be cut, formed, and welded; however, due to its high strength, its processing requirements are generally higher than those of ordinary carbon steel. When welding, specialized welding procedures should be developed based on factors such as plate thickness, carbon equivalent, heat input, preheating, and interpass temperatures; welding parameters for ordinary structural steel should not be directly applied.

6. Suitable for Heavy-Load, High-Stress Conditions

The high yield strength and tensile strength of S890Q make it suitable for manufacturing structural components subjected to significant static or dynamic loads.

1. Cranes and Heavy-Duty Lifting Equipment

S890Q is one of the key materials used in large mobile cranes, aerial work platforms, and heavy-duty lifting equipment.

Its primary applications include: crane booms, telescoping booms, boom connection components, outriggers, high-stress structures, and load-bearing components of lifting equipment.

By leveraging the high yield strength of S890Q, the thickness of steel plates and the structural weight can be reduced while still meeting load-bearing requirements, thereby enhancing the equipment’s lifting capacity and mobility.

2. Construction Machinery

S890Q is suitable for high-load structural components in various types of heavy-duty construction machinery, such as: excavator booms and dippers, loader structural components, bulldozer load-bearing parts, drill rig structures, electric shovels and large construction equipment, as well as heavy-duty construction machinery undercarriages and frames.

For components subjected to impact, bending, and cyclic loads, high-strength steel helps reduce structural weight while maintaining high load-bearing capacity.

3. Mining Machinery

Mining equipment typically faces significant static loads and dynamic impacts. S890Q can be used in: frames for mining dump trucks, mining transport equipment, hydraulic supports, load-bearing structures for mining equipment, structural components for crushing, loading, and conveying equipment, and mining drills.

In particular, coal mine hydraulic supports and heavy-duty mining equipment have a high demand for high-strength structural steel.

4. Heavy-Duty Vehicles and Transportation Equipment

S890Q can be used in vehicle structures that require both high load-bearing capacity and lightweight design, such as: heavy-duty truck frames, mining dump trucks, engineering transport vehicles, load-bearing beams for trailers and semi-trailers, and dump truck bodies and underbody structures.

Reducing structural weight provides vehicles with greater payload capacity.

5. High-Load Steel Structures

S890Q can also be used in certain specialized high-strength steel structures, such as bridges and bridge components, high-load support structures, steel gantries and large-scale supports, offshore engineering structures, large platforms, and support components.

However, due to S890Q’s high strength grade, it is typically selected in actual engineering projects when ordinary structural steel cannot meet load-bearing or weight-reduction requirements, rather than for general building steel structures.

6. Offshore Engineering and Energy Equipment

S890Q can also be used in certain high-strength offshore engineering and energy equipment, such as: offshore platform support structures, support components for offshore wind power equipment, offshore lifting equipment, pressure steel pipes for hydroelectric power stations, and load-bearing structures for large-scale energy equipment.

Welding Requirements:

Due to high strength, preheating is required before welding (typically 80–150°C, adjusted based on plate thickness and welding materials) to avoid cold cracks.

Low-hydrogen welding materials (e.g., ER110S-G welding wire, E11018-G electrodes) are recommended to match the base metal strength. Control the welding heat input to prevent toughness reduction due to overheating.

Cutting and Forming:

Plasma cutting or laser cutting is acceptable (control heat input to avoid edge embrittlement).

For cold forming (e.g., bending), control the bending radius (not less than 3× plate thickness) to prevent cracking.

Surface Treatment:

If used in corrosive environments (e.g., marine, mining), anti-corrosion treatment is required (e.g., sandblasting + anti-corrosion paint, hot-dip galvanizing). In some cases, weathering steel coatings may be applied.

In summary, EN 10025-6 S890Q is a premium, ultra-high-strength structural steel used in demanding applications where its superior strength-to-weight ratio justifies its higher cost and more complex fabrication requirements.